This invention relates to swim fins.
Swim fins each comprising a foot pocket and a blade extending forward from a front end of the foot pocket are well known in the art. The foot pocket includes a sole to come in contact with the wearer""s sole, an instep to come in contact with the wearer""s instep, and transverse opposite side walls extending between these sole and instep. Longitudinally opposite ends of a heel strap are fixed to outer surfaces of the side walls so that a length of the heel strap may be adjusted. The sole is sometimes provided on its inner surface with a plurality of ribs extending forward from the vicinity of an opening for foot insertion and projecting inwardly of the foot pocket. Such ribs facilitate the wearer""s feet wearing boots to be inserted into and drawn off from the respective foot pockets.
However, it may be impossible for the presence of the ribs provided on the sole alone to facilitate the insertion of the wearer""s feet into the respective foot pockets if the wearer""s feet are relatively large with respect to the size of the foot pockets. In this case, drawing off of the wearer""s feet from the respective foot pockets may be also difficult.
It is an object of this invention to provide swim fins designed so that the wearer""s feet may be easily inserted into and drawn out from respective foot pockets.
According to this invention, there is provided swim fins each comprising a foot pocket and a blade extending forward from a front end of the foot pocket.
The swim fins comprising the foot pocket further include a sole, an instep and transversely opposite side walls extending between the sole and instep. At least one of the sole and instep is provided on an inner surface thereof with a plurality of ribs extending forward from the vicinity of an opening for foot insertion and grooves each defined between each pair of the adjacent ribs so that the instep is thinner along the grooves than along the ribs and deformed more easily along the grooves than along the ribs.
The swim fins according to this invention advantageously facilitate the wearer to insert and to draw out his or her feet into and from the foot pockets of the insteps and the soles of the respective foot pockets, at least the insteps are provided on their inner surfaces with a plurality of ribs extending forward from the vicinity of the respective openings for feet insertion and the grooves each defined between each pair of the adjacent ribs. With the insteps of the respective foot pockets formed with the elastic material having a low rigidity, the thin grooves each defined between each pair of the adjacent ribs can be stretched to enlarge the circumferential dimension of the foot pockets and thereby to be adapted even for relatively large feet with respect to the foot pockets.